Algae in swimming pool. How to rid?

Clinton McClure · 06-26-2005, 09:17 PM

This past weekend I put up an 18' x 4' swimming pool and filled it. By the time it was full last night it was too late to get out and install the filter (3AM) so I put it off until this morning. I go out about 9:30 this morning and the water is pea green. Yuck! I didn't expect to get an algae bloom overnight within 6 hours.

After initial set-up was complete, I checked my water and the pH was 6.8. The set up instructions for the pool said to add pH increaser until desired level was achieved before chlorinating. So I added the increaser and waited a couple hours and rechecked. The pH was 7.2. The instructions then said to shock the pool so I did that and it jumped the pH up to over 8.

What's the best way to rid the pool of algae? I changed the filter cartridge after about 6 hours of operation because it had turned solid black and the water in the filter housing was black too.

Chris Bardon · 06-27-2005, 07:12 AM

You should just be able to buy algecide at the pool store. It's usually a liquid that comes in a tall bottle (about 1-1.5 litres I'd guess) and there should be directions on how much to add on the bottle.

I'm not sure what the normal operating pH should be though-8 seems a little high. Ideally I'd say as close to 7 as possible, but I think I'd probably err on the low end (6.5-7). Can't remember what's recommended, since I haven't lived with a pool for a few years now.

As for the pool turning green overnight, I remember dumping a whole load of liquid chlorine into our inground when we opened as kind of a "super-shock" to start things up. Since you're going from essentially tapwater to chlorinated water, a normal shock probably won't do the trick. Check your chlorine/bromine level and make sure it's high enough (your test kit probably has guidelines on what's a good level).

Jeff Blair · 06-27-2005, 07:38 AM

Ahhh, allege. I've been fighting that for about the past 2 weeks with my in-laws pool. I have used something called "Back to Blue" that worked well. Also, I picked up a crystal this past weekend called "Yellow Out". How they were telling me on how to do it is this. "Super" Shock your pool, and let it run for about 4 hours. Then put in the allege killer. Make sure that it runs for 24 hours. That should hopefully do it. If not put a sign on it, and call it a spa. They have allege "treatments" there right??

Fred Seger · 06-27-2005, 09:47 AM

Letting the filter run is very important for getting the water clear again also. And clean it often ( if its a cartridge filter).

Clinton McClure · 06-27-2005, 12:42 PM

Chris - Normal pH should be 7.2-7.8. This morning my reading is 8.4 with 0ppm available chlorine (should be between 1&4). I just added some pH decreaser and will shock treat again before I go to work. When I get home tonight I'll add algaecide.

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Kevin_Spradley · 06-27-2005, 12:59 PM

CLinton- Try to measure the total chlorine also, not just the free chlorine. As chlorine sanitizes it converts into chloramine. This will cause the free available chlorine to drop, but the total will still have reading. When the two readings differ by more than 0.5 ppm (or 1.0 ppm), it is a good idea to shock the pool. This will break up the chlorimine bonds and give you back free chlorine. How are you adding chlorine to the pool? through a floating chlorinator? Yellow Out is a very good treatment as it is a non-scrubbing treatment. I used Yellow Out at the beginning of the season, along with several other people, and we all ended up with very cloudy pools for a significantly length of time. Once that got straightened out, I had another algae problem. Remember, not all algae is the same. I decided to try the cheap algaecide from Wal-mart and that didn't work. So I bought the super concentrate algaecide from wal-mart, it worked like a charm. You will probably also need a product like Metal Free to use in conjuction with the algaecide. Feel free to ask any more questions, because if it a pool problem, I have probably endured it.

Chu Gai · 06-27-2005, 01:54 PM

Not only is the maintenance of the correct pH range important, but so is maintaining the correct level of alkalinity which will help in resisting (buffering) changes in pH. I'd recommend either testing your water yourself or just bring it in to a local pool place which will generally analyze your water for you and make specific recommendations to get your pool in chemical balance.

Kevin_Spradley · 06-27-2005, 02:40 PM

I forgot to mention anything about phosphates. Algae feeds on phosphates. Therefore, when you kill algae, they release phosphates. There is a product call PhosFree (NoPhos), etc that will eliminate the phosphates. I used this along with the algaecide to get rid of my algae. I use PhosFree as a maintenance also.

ZacharyTait · 06-27-2005, 05:55 PM

Just pee in it. That will help.